This study of the flow of online discussions examined how earlier messages affected later messages along five dimensions: (1) evaluations (agreement, disagreement, or unresponsive actions); (2) knowledge content (contribution, repetition, or null content); (3) social cues (positive, negative, or none); (4) personal information (number of visits); and (5) elicitation (eliciting response or not). Using sequential logit regressions and a structural equation model (SEM), this study analyzed 131 messages across seven topics in the mathematics forum of a university Bulletin Board System (BBS) Website. Results showed that a disagreement or contribution in the previous message increased the likelihoods of disagreements and social cue displays in the current message. Unlike face-to-face discussions, online discussion messages that disagreed with an earlier message were more likely to elicit responses. Together, these results support the claims that teachers can use and manage online discussions at the message level to promote critical thinking, facilitate discussion of controversial topics, and reduce status effects.